The long range goal of this project is to use immunocytochemical staining along with light and electon microscopy to study the cellular mechanisms of myelin formation, breakdown and regeneration. Nervous tissues from experimental animals and humans have been studied in the following current projects: 1) Localization of myelin-associated glycoprotein (MAG) in developing and mature nervous tissue, 2) Distribution of MAG and myelin basic protein (BP or P1) in multiple sclerosis (MS) lesions, 3) Comparison of the distribution of BP, small myelin basic protein (P2) and the major peripheral glycoprotein (Po) in peripheral myelin sheaths, and 4) Use of ethanolic phosphotungstic acid (E-PTA) to study the distribution of basic proteins in the cytoplasm of myelin forming oligodendrocytes.